Voltage adjustment system

ABSTRACT

A voltage adjustment system includes a power supply for providing an initial voltage signal, a plurality of buck converters for receiving the initial voltage signal and generating one adjustable output voltage signal respectively, a microcontroller for determining one adjustable output voltage signal to output and determining whether a variable voltage signal generated by a buck converter that outputs the adjustable output voltage signal is positive or negative, a display unit for displaying value of the adjustable output voltage signal that is outputted, a plurality of voltage control units corresponding to the plurality of buck converters, and a voltage variation adjustment circuit including two buttons. The variable voltage signal is added to the adjustable output voltage signal generated by the same buck converter. Selection of the two buttons causes the microcontroller to adjust absolute value of the variable voltage signal generated by the buck converter through the corresponding voltage control unit.

BACKGROUND

1. Technical Field

The present disclosure relates to a voltage adjustment system, andparticularly to a voltage adjustment system for electrical testing ofelectronic devices.

2. Description of Related Art

Many electronic devices such as computers may require electrical testingbefore delivery. Different operating circuits of the electronic devicerequire different operating voltages during the electrical testingprocess. For example, electrical testing an electronic device mayrequire operating voltages of 3.3 volts, 5 volts, and 12 volts, and whentesting whether the electronic device works abnormally when theoperating voltages have slightly changed, the operating voltages of 3.3volts, 5 volts, and 12 volts may need to be slightly adjusted.

Different power supplies are needed to provide different operatingvoltages, and voltage adjustment circuits are needed to slightly adjustthe operating voltages. Thus, many testing equipments lead to circuitcomplexity, and high cost.

Therefore, it is desired to provide a voltage adjustment system whichcan overcome the above-described deficiencies.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present voltage adjustment system can be betterunderstood with reference to the following drawings. The components inthe various drawings are not necessarily drawn to scale, the emphasisinstead being placed upon clearly illustrating the principles of thepresent voltage adjustment system.

FIG. 1 is a block diagram of a voltage adjustment system according toone embodiment of the present disclosure.

FIG. 2 is a circuit diagram of one embodiment of a buck converter and avoltage control unit of the voltage adjustment system shown in FIG. 1.

FIG. 3 is a circuit diagram of one embodiment illustrating electricalconnections between a microcontroller, selection switches, abidirectional switch, and a display unit of the voltage adjustmentsystem shown in FIG. 1.

FIG. 4 is a circuit diagram of one embodiment of a voltage variationadjustment circuit of the voltage adjustment system shown in FIG. 1.

FIG. 5 is a circuit diagram of one embodiment illustrating electricalconnections between the buck converter and the microcontroller of thevoltage adjustment system shown in FIG. 1.

DETAILED DESCRIPTION

Referring to FIG. 1, a voltage adjustment system 100 according to anexemplary embodiment of the present disclosure includes a power supply10, a plurality of buck converters 11 electronically connected to thepower supply 10, an analog-to digital converter (ADC) 12, amicrocontroller 13, a demultiplexer 14, a plurality of voltage controlunits 15, a voltage variation adjustment circuit 16, a plurality ofselection switches 17 corresponding to the plurality of buck converters11, a bidirectional switch 18, and a display unit 19. The plurality ofbuck converters 11 are electronically connected to the ADC 12, and eachbuck converter 11 is electronically connected to a voltage control unit15. The plurality of voltage control units 15 are electronicallyconnected to the demultiplexer 14 and the voltage variation adjustmentcircuit 16. The plurality of buck converters 11, the ADC 12, thedemultiplexer 14, the voltage variation adjustment circuit 16, theplurality of selection switches 17, the bidirectional switch 18, and thedisplay unit 19 are all electronically connected to the microcontroller13. The number of the buck converters 11, the voltage control units 15,and the selection switches 17 are the same, and determined by the numberof desired output voltage signals. In this embodiment, the number of thedesired output voltage signals is four.

Referring to FIG. 2, each buck converter 11 includes a voltage terminalVCC5, a function terminal VMSET/MODE, two general purpose input/outputterminals GPIO1/REFIN, GPIO2. Each voltage control unit 15 includes ann-channel transistor Q1, a digital potentiometer 151, and two currentlimiting resistors R. A drain electrode of the transistor Q1 iselectronically connected to the voltage terminal VCC5, a sourceelectrode of the transistor Q1 is electronically connected to thefunction terminal VMSET/MODE, and a gate electrode of the transistor Q1is electronically connected to a 5 volts input terminal through acurrent limiting resistor R.

The digital potentiometer 151 includes three control terminals INC, CS,U/ D and three resistor terminals RH, RW, RL. The three controlterminals INC, CS, U/ D are operable to receive control signalsaccording to which a resistance of the digital potentiometer 151 isadjusted. The resistor terminal RH is floating, the resistor terminal RWis electronically connected to the function terminal VMSET/MODE, and theresistor terminal RL is grounded through a current limiting resistor R.The digital potentiometer 151 can be referred to as a rheostat that isdigitally controlled, the resistor terminal RW can be referred to as awiper terminal of the rheostat, and the resistor terminals RH, RL can bereferred to as two ends of the rheostat. The operation modes of thedigital potentiometer 151 are shown in the following table, and “X” inthe table is capable of representing any value.

INC CS U/ D Operation high to low low high wiper terminal toward RH highto low low low wiper terminal toward RL High low to high X store wiperterminal position

Referring to FIG. 3, in this embodiment, the microcontroller 13 is asingle chip microcomputer. The microcontroller 13 includes a pluralityof pins P1.0˜P1.7, P2.0˜P2.2, P2.5˜P2.6. Each of the pins P1.0˜P1.3 isgrounded through a selection switch 17. Each selection switch 17 iselectronically connected to a 5 volts input terminal through a currentlimiting resistor R. According to switch states of the selectionswitches 17, the pins P1.4, P1.5 outputs selection signals to the ADC 12and the demultiplexer 14. The pin P1.6 is electronically connected tothe bidirectional switch 18. According to selection of the bidirectionalswitch 18, the pin P1.7 outputs a voltage variation control signal tothe general purpose input/output terminal GPIO1/REFIN. The pin P2.0 iselectronically connected to the control terminal U/ D. The pins P2.1,P2.2 are electronically connected to the voltage variation adjustmentcircuit 16. The pins P2.5, P2.6 are electronically connected to thedisplay unit 19.

Referring to FIG. 4, the voltage variation adjustment circuit 16includes four n-channel transistors Q2, Q3, Q4, Q5, a plurality ofcurrent limiting resistors R, and two buttons SW1, SW2. The controlterminal INC of each digital potentiometer 151 is grounded through thetransistor Q2, and the control terminal INC of each digitalpotentiometer 151 is also grounded through the transistor Q3. A gateelectrode of the transistor Q2 and a gate electrode of the transistor Q4are electronically connected to the button SW1. The gate electrode ofthe transistor Q4 is grounded through a current limiting resistor R, adrain electrode of the transistor Q4 is electronically connected to thepin P2.1, and a source electrode of the transistor Q4 is grounded. Agate electrode of the transistor Q3 and a gate electrode of thetransistor Q5 are electronically connected to the button SW2. The gateelectrode of the transistor Q5 is grounded through a current limitingresistor R, a drain electrode of the transistor Q5 is electronicallyconnected to the pin P2.2, and a source electrode of the transistor Q5is grounded. The two buttons SW1, SW2 are electronically connected to a5 volts input terminal.

Referring to FIG. 5, the pin P1.7 is electronically connected to thegeneral purpose input/output terminal GPIO1/REFIN. The general purposeinput/output terminal GPIO1/REFIN is electronically connected to a gateelectrode of a transistor Q6. A drain electrode of the transistor Q6 iselectronically connected to the general purpose input/output terminalGPIO2. A source electrode of the transistor Q6 is grounded. The generalpurpose input/output terminal GPIO2 is electronically connected to a 5volts input terminal through a current limiting resistor R.

Referring to FIGS. 1-5, the voltage adjustment system 100 functions asfollows:

The power supply 10 sends an initial voltage signal to the four buckconverters 11. The four buck converters 11 receive the initial voltagesignal and generate four different output voltage signals V1, V2, V3,and V4 respectively. When the selection switch 17 corresponding to thebuck converter 11 that generate the output voltage signal V1 is closed,the microcontroller 13 sends selection signals ADD-A, ADD-B to the ADC12 and the demultiplexer 14 through the pins P1.4, P1.5. According tothe selection signals ADD-A, ADD-B, the ADC 12 collects the outputvoltage signal V1, converts the output voltage signal V1 into a digitalsignal, and sends the digital signal to the microcontroller 13. Themicrocontroller 13 sends a display control signal to the display unit19. The display unit 19 receives the display control signal and displaysthe value of the output voltage signal V1. The demultiplexer 14 receivesthe selection signals ADD-A, ADD-B and sends a low level signal (logic0) Margin S1 to a voltage control unit 15 connected to the buckconverter 11 that generate the output voltage signal V1. The voltagecontrol unit 15 receives the low level signal Margin S1, and the lowlevel signal Margin S1 is applied to the control terminal CS of thedigital potentiometer 151 and the gate electrode of the transistor Q1.According to the low level signal Margin S1, the transistor Q1 turnsoff, then the function terminal VMSET/MODE is disconnected from thevoltage terminal VCC5, and the buck converter 11 that generate theoutput voltage signal V1 generates a variable voltage signal ΔV_(OUT)added to the output voltage signal V1. That is the variable voltagesignal ΔV_(OUT) is added to the output voltage signal V1 generated bythe same buck converter 11.

When there is a need to slightly adjust the value of the output voltagesignal V1, users may choose to increase or decrease the value of theoutput voltage signal V1 through the bidirectional switch 18. If thevalue of the output voltage signal V1 needs to be increased, themicrocontroller 13 sends a low level signal (logic 0) to the generalpurpose input/output terminal GPIO1/REFIN through the pin P1.7. Then thetransistor Q6 turns off, the voltage of the general purpose input/outputterminal GPIO2 is at a high logic level, and then the variable voltagesignal ΔV_(OUT) is positive. If the value of the output voltage signalV1 needs to be decreased, the microcontroller 13 sends a high levelsignal (logic 1) to the general purpose input/output terminalGPIO1/REFIN through the pin P1.7. Then the transistor Q6 turns on, thevoltage of the general purpose input/output terminal GPIO2 is at a lowlogic level, and then the variable voltage signal ΔV_(OUT) is negative.

The adjustment process of the absolute value of the variable voltagesignal ΔV_(OUT) is as follows:

If the absolute value of the variable voltage signal ΔV_(OUT) needs tobe increased, the button SW2 is pressed. Then the transistors Q3, Q5turn on, the voltage of the control terminal INC changes from logic highto logic low, and the voltage of the pin P2.2 changes from logic high tologic low. The microcontroller 13 sends a low level signal (logic 0) tothe control terminal U/ D through the pin P2.0. Referring to theabove-mentioned table, the resistance between the resistor terminal RWand the resistor terminal RL is decreased. In this embodiment, theabsolute value of the variable voltage signal ΔV_(OUT) is inverselyproportional to the resistance between the resistor terminal RW, andthen the absolute value of the variable voltage signal ΔV_(OUT) isincreased.

If the absolute value of the variable voltage signal ΔV_(OUT) needs tobe decreased, the button SW1 is pressed. Then the transistors Q2, Q4turn on, the voltage of the control terminal INC changes from logic highto logic low, and the voltage of the pin P2.1 changes from logic high tologic low. The microcontroller 13 sends a high level signal (logic 1) tothe control terminal U/ D through the pin P2.0. Referring to theabove-mentioned table, the resistance between the resistor terminal RWand the resistor terminal RL is increased, and then the absolute valueof the variable voltage signal ΔV_(OUT) is decreased. The adjustedoutput voltage signal V1 is displayed on the display unit 19.

As detailed above, according to an initial voltage signal, the voltageadjustment system 100 generates a plurality of adjustable output voltagesignals and is easily operated.

It is to be further understood that even though numerous characteristicsand advantages of the present embodiments have been set forth in theforegoing description, together with details of structures and functionsof various embodiments, the disclosure is illustrative only, and changesmay be made in detail, especially in matters of shape, size, andarrangement of parts within the principles of the present disclosure tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed.

What is claimed is:
 1. A voltage adjustment system, comprising: a powersupply for providing an initial voltage signal; a plurality of buckconverters for receiving the initial voltage signal and generating oneadjustable output voltage signal respectively; a microcontroller fordetermining one of the adjustable output voltage signals to output anddetermining whether a variable voltage signal generated by a buckconverter that outputs the adjustable output voltage signal is positiveor negative; a display unit for displaying value of the adjustableoutput voltage signal that is outputted; a plurality of voltage controlunits; and a voltage variation adjustment circuit including two buttons;wherein each voltage control unit corresponds to one buck converter; thevariable voltage signal is added to the adjustable output voltage signalgenerated by the same buck converter; selection of the two buttonscauses the microcontroller to adjust absolute value of the variablevoltage signal generated by the buck converter through the correspondingvoltage control unit.
 2. The voltage adjustment system as claimed inclaim 1, wherein each voltage control unit comprises a digitalpotentiometer electronically connected to the corresponding buckconverter.
 3. The voltage adjustment system as claimed in claim 2,wherein the voltage variation adjustment circuit further comprises twotransistors electronically connected to the digital potentiometer, andtwo transistors electronically connected to the microcontroller; eachbutton of the voltage variation adjustment circuit is electronicallyconnected to one transistor connected to the digital potentiometer andone transistor connected to the microcontroller.
 4. The voltageadjustment system as claimed in claim 3, wherein the voltage adjustmentsystem further comprises a bidirectional switch electronically connectedto the microcontroller, according to selection of the bidirectionalswitch, the microcontroller determines the variable voltage signalgenerated by the buck converter is positive or negative.
 5. The voltageadjustment system as claimed in claim 4, wherein when one of the buttonsis pressed, the two transistors electronically connected to the pressedbutton turns on at the same time.
 6. The voltage adjustment system asclaimed in claim 4, wherein according to the selection of the buttons,the microcontroller sends control signals to the digital potentiometers;according to the control signals, the resistance of the digitalpotentiometer electronically connected to the buck converter thatgenerate the variable voltage signal is adjusted to increase or decreasethe absolute value of the variable voltage signal.
 7. The voltageadjustment system as claimed in claim 6, wherein the voltage adjustmentsystem further comprises a plurality of selection switcheselectronically connected to the microcontroller, and each selectionswitch corresponds to one buck converter.
 8. The voltage adjustmentsystem as claimed in claim 6, wherein the voltage adjustment systemfurther comprises a demutiplexer electronically connected to themicrocontroller, the demutiplexer is electronically connected to theplurality of voltage control units.
 9. A voltage adjustment system,comprising: a power supply; a plurality of buck converters forgenerating a plurality of adjustable output voltage signals; amicrocontroller; a plurality of voltage control units corresponding tothe plurality of buck converters; a voltage variation adjustment circuitelectronically connected to the plurality of voltage control units; anda display unit; wherein the plurality of buck converters areelectronically connected to the power supply; each voltage control unitis electronically connected to the corresponding buck converter; theplurality of buck converters, the voltage variation adjustment circuit,and the display unit are electronically connected to themicrocontroller.
 10. The voltage adjustment system as claimed in claim9, wherein each voltage control unit comprises a digital potentiometerelectronically connected to the corresponding buck converter.
 11. Thevoltage adjustment system as claimed in claim 10, wherein the voltagevariation adjustment circuit comprises two buttons, two transistorselectronically connected to the digital potentiometer, and twotransistors electronically connected to the microcontroller; each buttonis electronically connected to one transistor connected to the digitalpotentiometer and one transistor connected to the microcontroller. 12.The voltage adjustment system as claimed in claim 11, wherein thevoltage adjustment system further comprises a bidirectional switchelectronically connected to the microcontroller, the microcontrollerdetermines one adjustable output voltage signal to output, and accordingto selection of the bidirectional switch, the microcontroller determineswhether a variable voltage signal generated by the buck converter thatoutput the adjustable output voltage signal is positive or negative. 13.The voltage adjustment system as claimed in claim 12, wherein thevariable voltage signal is added to the adjustable output voltage signalgenerated by the same buck converter.
 14. The voltage adjustment systemas claimed in claim 13, wherein when one of the buttons is pressed, thetwo transistors electronically connected to the pressed button turns onat the same time.
 15. The voltage adjustment system as claimed in claim13, wherein according to the selection of the buttons, themicrocontroller sends control signals to the digital potentiometers;according to the control signals, the resistance of the digitalpotentiometer electronically connected to the buck converter thatgenerate the variable voltage signal is adjusted to increase or decreasethe absolute value of the variable voltage signal.
 16. The voltageadjustment system as claimed in claim 15, wherein the voltage adjustmentsystem further comprises a plurality of selection switcheselectronically connected to the microcontroller, and each selectionswitch corresponds to one buck converter.
 17. The voltage adjustmentsystem as claimed in claim 15, wherein the voltage adjustment systemfurther comprises a demutiplexer electronically connected to themicrocontroller, the demutiplexer is electronically connected to theplurality of voltage control units.